wow thats quite a price, I hope the rest of its pristine!
I got my 88 R2J running, but very manky and poor condition as a track bike for $700nz so about $500usd. I would've expected a nice condition road legal MC18 to be worth ~3k US max - but thats here I guess.
De-restricting is covered elsewhere on the site menu to the left, the 88 MC18 R2J is easy as can be simply disconnecting a bullet connector does it. The 89 R5k is a bit harder but still very straight forward.
go on, get one you know you want to